PCAN-Driver for Linux

PCAN-driver for Linux

PCAN-driver for Linux page 1 of 20 History of the document first draft Hi 13.01.2002 rescue after loss of data Hi 10.02.2002 format revision, read/write tables Hi 20.02.2002 delete typographic mistakes Hi 21.02.2002 PCAN-USB integrated Hi 09.02.2003 obfuscation of „pcan_usb_kernel.c“ is described Hi 23.02.2003 devfs, kernel-2.5 support, LGPL Hi 04.08.2003 1st revision for kernel 2.6.x Hi 02.05.2004 enlarge FAQ, corrections Hi 13.05.2004 simple correction for RPM make procedure Hi 14.08.2004 additional compiler switches Hi 19.07.2005

PCAN-driver for Linux page 2 of 20 table of documents Disclaimer...... 4 Characteristics of the 'pcan.o' or 'pcan.ko' driver...... 4 Characteristics of the 'libpcan.so' library...... 5 Preliminary notes...... 5 Installation with RPM...... 6 Installation of source RPM...... 6 Customization of 'modules.conf' or 'modprobe.conf'...... 7 Installation of the driver ...... 7 Manual installation...... 7 Manual file unpacking ...... 7 Specifics with the driver installation for PCAN-USB ...... 8 Manual installation of the driver ...... 9 Manual installation of the shared library...... 10 Manual installation of the header-files...... 10 Semi-automatic installation with translation...... 11 Installation test, use of test programs...... 11 Most important header files ...... 13 Compilation of the driver...... 13 Use cases ...... 13 Prerequisites for compilation of the sources...... 14 Support for Cross-Compilation...... 15 FAQs...... 15 Appendix...... 19

PCAN-driver for Linux page 3 of 20 Disclaimer Part of this program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License or LGPL Lesser General Public License as published by the Free Software Foundation version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

It is strictly prohibited to use the intellectual property from the provided source code for developing or producing a 'compatible' hardware. All rights are reserved by Peak- System- Technik GmbH.

Characteristics of the 'pcan.o' or 'pcan.ko' driver The „pcan.o“ or „pcan.ko“ driver is supporting PCAN-PCI, PCAN-ISA, PCAN-PC/104, PCAN-Dongle as well as PCAN-USB hardware. Depending on the type of hardware (PCI, ISA, Dongle, USB) 8 channels for each type can be supported. For PCAN-ISA, PCAN-PC/104 and PCAN-Dongle the base address and the used interrupt are adjustable. If no parameters are provided then the driver uses factory defaults. A user program can communicate with the driver in two different ways: 1. ASCII formatted data can be provided or accepted over a „read()“ or „write()“ interface. This data contains information from received or transmitted telegrams or about channel initializing parameters. 2. With a „ioctl()“ interface. Through this interface user programs are able to receive and to transmit CAN-telegrams as well. However it is possible to get information about the diagnosis of the channel status and to initialize the CAN-channel. The driver can be used from more than one user program at the same time and the simultaneous use of lots of interfaces and/or CAN channels is supported. If more than one user program communicates with the same CAN-channel the input or output is shared. (e.g.: Many user programs are accidentally sharing the received telegrams.) Up from Release_20030622_x the device file system is being supported optionally. Using the devfs it's not necessary to create device files manually any more. This is taken over by the kernel in cooperation with the driver and the daemon devfsd. The device file system has to be enabled within the kernel. (From kernel version 2.6.x on the kernel developers depreciate the use of devfs so for the time being the driver is not supporting this.) The reading or writing of telegrams can block if the receive buffer doesn't contain data any more or if the write buffer is full. This behaviour can be disabled by opening the path as non-blocking.

PCAN-driver for Linux page 4 of 20 The „select“-method is supported. The interface to the driver (constants and structures) is defined in the header file „pcan.h“.

Characteristics of the 'libpcan.so' library The „libpcan.so“ library is providing an easier interface for using the properties of the PCAN-drivers. The library interface is similar to the ones from MS-Windows and make the porting of applications easier. There are also some calls which adapt better to the specifics of Linux. They are marked with a 'LINUX_..' as prefix. (Example: HANDLE LINUX_CAN_Open(char *szDeviceName, int nFlags);)

Application

Shared library

Driver

Picture 1. calling hierarchy

The interface of the library is described within the C/C++-header file „libpcan.h“. Please note that „libpcan.h“ includes the „pcan.h“ file. The source code is under LGPL so it is for utilizing within proprietary software without any exceptions.

Preliminary notes Note: Before installing the software the hardware has to be installed in or at the computer (Exception: PCAN-Dongle or PCAN-USB, see at (6*)). This manual is describing the installation process on a x86-Linux-computer with installed kernel 2.4.x. and a SuSE 8.0 system. Exceptions for kernel 2.2.x. 2.6.x and x86-RedHat systems are particularly mentioned. During the installation sometimes a console and perhaps an editor as well will be used in the „root“- mode. If you want to login as „root“ user within a console or xterm-session you can use the 'su' command or the built in menu „file/root console“.

PCAN-driver for Linux page 5 of 20 To start an editor in the „root“ – mode, just invoke from the menu „system/terminals/terminal (system manager mode)“ in KDE. From the console command line you can invoke the editor „kwrite“, „kate“ or „emacs“. For some distributions the standard path doesn't include the „/sbin“ folder. Then installation commands have to typed in with „/sbin/“ ahead. Examples: /sbin/modprobe ... instead of modprobe ... /sbin/insmod ... instead of insmod ... /sbin/rmmod ... instead of rmmod ... /sbin/modinfo ... instead of modinfo ...

Installation with RPM The installation comprise three files: Installation-en.pdf description in PDF format. peak-linux-driver-20040501-3.3.src.rpm the RPM-source-file. peak-linux-driver.3.3.tar.gz the packed tar-sources.

(Note: The term for release or the version for file names can change.) The installation with RPM creates an installable RPM – package with standard settings for the local target system. If the standard settings don't fit you can do a manual installation.

Installation of source RPM Please type in the command line (as „root“ user): rpm --rebuild peak-linux-driver-20040501-3.3.src.rpm or rpmbuild –rebuild peak-linux-driver-20040501-3.3.src.rpm if the file „peak-linux-driver-20040501-3.3.src.rpm“ is in your current directory. This invocation expects the previous installation of the gcc-compiler, the kernel-headers and the make tools. The translation with and for systems with kernel 2.6.x needs an additionally configured kernel and all of the kernel sources. At the successful end of this rebuild RPM is filing at: „/usr/src/packages/“ or „/usr/src/redhat“ a system specific binary-installation for SuSE or RedHat in this folder. e.g. /usr/src/redhat/RPMS/i386/peak-linux-driver-20040501-3.3.i386.rpm

Now you can do the installation of the binary package: rpm --install peak-linux-driver-20040501-3.3.i386.rpm

PCAN-driver for Linux page 6 of 20 Alternatively you can use the GUI based installers „kpackage“ in KDE or „gnorpm“ in GNOME, too.

Customization of 'modules.conf' or 'modprobe.conf' For kernel version 2.6.x the role of the configuration file has been taken over by the 'modprobe.conf' file. Both files are to find in „/etc“. At the end of the „/etc/modules.conf“ file („modprobe.conf“) a marked addition is added through the installation. The respective type and the eventually non-standard base addresses and interrupt numbers are to be given there, if the driver have to support the PCAN-ISA or PCAN-Dongle interfaces. (Have a look at the description about the manual installation of the driver) Note: As soon as there already is an entry with the word 'pcan' the current entry is not to be changed. If you wish to have a new entry you have to delete the old one first. To do that you have to use an editor as „root“ user.

Installation of the driver After rebuilding the sources and the following binary installation on your target computer it's enough to type in /sbin/modprobe pcan to install the driver and any other useful modules. Depending on your requirements you have to do this procedure every time you start your computer or your application. (This may be done in a start up script, too.)

Manual installation

Manual file unpacking Unpack the file „peak-linux-driver.x.y.tar.gz“ into an optional folder into your home directory. Example: tar -xzf peak-linux-driver.3.3.tar.gz

Within this directory you get following tree of files:

Specifics with the driver installation for PCAN-USB For using the driver the USB subsystem of the Linux kernel has to be enabled. USB support for Linux was first introduced with kernel 2.4. The use of PCAN-USB together with a Linux kernel version less than 2.4.7 is deprecated through the driver developer.

PCAN-driver for Linux page 8 of 20 Manual installation of the driver Note: From the kernel version 2.6.0 on the kernel module extension is „ko“. This is why „pcan.o“ is named „pcan.ko“ from kernel 2.6.0 on. Register as „root“ user in a console e.g. konsole or xterm. Fork to the „.../peak-linux- driver-x.y/driver“ directory. Type in: /sbin/modprobe parport

This command installs the „Parport Subsystem“ with Linux. It is necessary to support the PCAN-Dongle integration (1*, 2*). If the command exits without an error message please invoke /sbin/insmod pcan.o type=xxx,yyy,... io=0x300,0x378,... irq=10,7,... or from kernel 2.6.0 on: /sbin/insmod pcan.ko type=xxx,yyy,... io=0x300,0x378,... irq=10,7,...

If you need USB support you have to do the same steps as in „Specifics with the driver installation for USB-PCAN“. The place holder „xxx,yyy,...“ are standing for „isa“, “sp“ or „epp“. The parameter for „io“ and „irq“ can be left out, if the standard assignments are configured with your hardware. PCI-channels and USB-channels are found and installed without any special details but ISA (PC/104) and parallel-Port supported channels have to be registered. The standard assignments for ISA and PC/104 interfaces are (io/irq): 0x300/10, 0x320/5 The standard assignments for Dongle in SP/EPP mode are (io/irq): 0x378/7, 0x278/5 With the following command you can see any error report (as „root“ user): tail /var/log/messages

Normally the output looks similar to this: Jan 13 18:28:57 sylvia kernel: pcan: *Name: Release_20020113_a * Jan 13 18:28:57 sylvia kernel: pcan: pci device minor 0 found Jan 13 18:28:57 sylvia kernel: pcan: isa device minor 8 found (io=0x0300,irq=10) Jan 13 18:28:57 sylvia kernel: pcan: epp-dongle device minor 24 prepared (io=0x0378,irq=7) Jan 13 18:28:57 sylvia kernel: pcan: major 254.

You can check the correct installation. Please invoke: cat /proc/pcan

You get a similar printout if there are no errors: *------PEAK-Systems CAN interfaces (www.peak-system.com) ------*------*Name: Release_20030208_u * ------*------6 interfaces @ major 254 found ------*n typ ---base--- ir ---read------write-- ---irqs------error-- status 0 pci 0xdb008000 5 0x00000000 0x00000000 0x00000000 0x00000000 0x0000 1 pci 0xdb008400 5 0x00000000 0x00000000 0x00000000 0x00000000 0x0000 8 isa 0x00000300 10 0x00000000 0x00000000 0x00000000 0x00000000 0x0000 24 epp 0x00000378 7 0x00000000 0x00000000 0x00000000 0x00000000 0x0000 32 usb 0x12340020 33 0x00000000 0x00000000 0x00000000 0x00000000 0x0000 33 usb 0x12340021 34 0x00000000 0x00000000 0x00000000 0x00000000 0x0000 The driver is configured for the dynamic allocation of the „major“ serial number (4*). This is why the device files have to be generated newly every time after driver installation. Please invoke the shell script for this:

PCAN-driver for Linux page 9 of 20 ./pcan_make_devices 2

This script installs two device files for each PCI, ISA, Dongle Devices in SP and EPP mode (3*) and USB-devices. Please verify the result with the command: ls -l /dev/pcan*

Now you already can do your first test with your CAN hardware. Just connect a CAN- transmitter to your CAN interface and send telegrams with bit rate setting of 500 kbit/sec . Login at a user-console and invoke: cat /dev/pcan0 for the first PCAN-PCI interface cat /dev/pcan8 for the first PCAN-ISA or PCAN-PC/104 interface cat /dev/pcan16 for the first PCAN-Dongle interface in SP-mode cat /dev/pcan24 for the first PCAN-Dongle interface in EPP-mode cat /dev/pcan32 for the first PCAN-USB interface (*9)

The received telegrams should be shown (5*). This invocation can be made at more than one console for more than one interface at the same time. The output of data is already possible. With the call of: echo „m s 0x234 2 0x11 0x22“ > /dev/pcan0 for example a CAN telegram with standard frame is transmitted with the identifier 0x234 and two data bytes „0x11“ and „0x22“ from the first PCAN-PCI interface. The bit rate of the interface can as well be set from the so called „write interface“.

Manual installation of the shared library Please change to the directory „../peak-linux-driver-x.y/lib“. Login as „root“ user and invoke: cp libpcan.so.0.1 /usr/lib/libpcan.so.0.1 ln -sf /usr/lib/libpcan.so.0.1 /usr/lib/libpcan.so.0 ln -sf /usr/lib/libpcan.so.0 /usr/lib/libpcan.so

This process is only necessary if you install this program for the first time or if you want to update the library. To use the test programs the library has to be installed.

Manual installation of the header-files Please copy the header-files into the directory „/usr/include“ as “root” user as followed and customize the access rights. cp peak-linux-driver/driver/pcan.h /usr/include/pcan.h chmod 644 /usr/include/pcan.h cp peak-linux-driver/lib/libpcan.h /usr/include/libpcan.h chmod 644 /usr/include/libpcan.h

PCAN-driver for Linux page 10 of 20 Semi-automatic installation with translation A semi-automatic installation with translation can also be done with little input. Unpack the tar.gz-files to „any-directory“ and start compilation and installation. Please note the prerequisites for compilation of the sources.

cp peak-linux-driver.3.3.tar.gz cd any-directory tar -xzf peak-linux-driver.3.3.tar.gz rm peak-linux-driver.3.3.tar.gz cd peak-linux-driver make clean make make install

Installation test, use of test programs Two test programs are attached for the initial test of the interfaces. For using the programs please change to the directory „.../peak-linux-driver-x.y/test“. Please invoke „/receivetest --help“. You get following response: receivetest Version "Release_20040412_a" (www.peak-system.com) ------Copyright (C) 2004 PEAK System-Technik GmbH ------receivetest comes with ABSOLUTELY NO WARRANTY. This is free software and you are welcome to redistribute it under certain conditions. For details see attached COPYING file.

receivetest - a small test program which receives and prints CAN messages. usage: receivetest {[-f=devicenode] | {[-t=type] [-p=port [-i=irq]]}} [-b=BTR0BTR1] [-e] [-?] options: -f - devicenode - path to devicefile, default=/dev/pcan0 -t - type of interface, e.g. 'pci', 'sp', 'epp', 'isa' or 'usb' (default: pci). -p - port in hex notation if applicable, e.g. 0x378 (default: 1st port of type). -i - irq in dec notation if applicable, e.g. 7 (default: irq of 1st port). -b - BTR0BTR1 code in hex, e.g. 0x001C (default: 500 kbit). -e - accept extended frames. (default: standard frames) -? or --help - this help

receivetest: finished (0). The default bit-rate settings for all CAN-interfaces are set to 500 kbit/sec. The bit rate can be customized through the command line parameters. For using a ISA or Dongle interface with the standard settings following detail is enough: receivetest -t=isa or receivetest -t=sp or receivetest -t=epp or receivetest -f=/dev/pcan0 to get to the first PCAN-PCI-interface.

Every received telegram of the interface will be print out. Entering Ctrl-C cancels the program. The program „transmitest“ can be used to transmit data. Please invoke „./transmitest – help“. You get following output similar to receivetest: transmitest Version "Release_20040412_a" (www.peak-system.com) ------Copyright (C) 2004 PEAK System-Technik GmbH ------

PCAN-driver for Linux page 11 of 20 transmitest comes with ABSOLUTELY NO WARRANTY. This is free software and you are welcome to redistribute it under certain conditions. For details see attached COPYING file.

transmitest - a small test program which sends CAN messages. usage: transmitest filename {[-f=devicenode] | {[-t=type] [-p=port [-i=irq]]}} [-b=BTR0BTR1] [-e] [-?] options: filename - mandatory name of message description file. -f - devicenode - path to devicefile, default=/dev/pcan0 -t - type of interface, e.g. 'pci', 'sp', 'epp' ,'isa' or 'usb' (default: pci). -p - port in hex notation if applicable, e.g. 0x378 (default: 1st port of type). -i - irq in dec notation if applicable, e.g. 7 (default: irq of 1st port). -b - BTR0BTR1 code in hex, e.g. 0x001C (default: 500 kbit). -e - accept extended frames. (default: standard frames) -? or --help - this help

transmitest: finished (0).

This program expects similar parameters as receivetest with the exception of a file name. In the file with this name the program expects a list of telegram descriptions which are to be send. Those telegrams will be send cyclic until the ending by pressing Ctrl-C. The syntax of the description of the telegrams is:

Tag / Column #1 Description m Message string follows r RTR-Message string follows i Initialisation string follows (write only) # Comment follows (write only) Description of the first column of the telegram of the read/write interface.

Column Description 2 s = Standard frame, e = Extended frame 3 Identifier (hex) 4 Length of telegram (dec) 5..12 Telegram bytes (hex) 13 Timestamp (dec, read only) 13 Comment (write only) Description of the following columns of 'normal' and RTR-telegrams.

Column Description 2 BTR0BTR1 Init data (hex, write only) 3 e = allow extended frames (write only) Description of the following columns for initializing strings.

For example:

# a comment # a message, standard frame, id=0x123, 0 Data bytes m s 0x123 0 # a message, standard frame, id=0x123, 1 Data byte, Data m s 0x123 1 0x11 # a message, standard frame, id=0x123, 1 Data byte, Data m s 0x123 2 0x11 0x22 # a message, extended frame, id=0x123, 3 Data byte, Data m e 0x123 3 0x11 0x22 0x33 # a RTR, standard frame, id=0x123, 0 Data byte, comment

PCAN-driver for Linux page 12 of 20 r s 0x123 0 # a comment # a RTR, extended frame, id=0x123, 0 Data byte, comment r e 0x123 0 # a comment # initialize i 0x1234 e

Most important header files Any sources of the driver, of the library and the test programs are fit in underneath the „peak-linux-driver-x.y“ directory tree. Two files are to be mentioned especially: The file „.../peak-linux-driver/driver/pcan.h“ describes the interface to the driver and command constants. You have to include this file if you want to have direct access to the driver with „open(), ioctl(), read(), close() etc.“. The file „.../peak-linux-driver/lib/libpcan.h“ describes the interface to the dynamic linkable library libpcan.so. You have to include this file if your application needs to use the dynamic library. Please note that libpcan.h is including the pcan.h file.

Compilation of the driver

Use cases In some cases of using the installed driver it doesn't fit to the configured operating system. This could be following cases: 1. Your kernel sources are not to be found in the standard directory „/usr/src/linux“. You still can compile with following invocations: cd ~/peak-linux-driver/driver make clean make KERNEL_LOCATION= 2. You don't need or don't want support for some interface types. Then you have to compile the driver with disabled support for some interfaces. The makefile provides to enable or disable partial compilation with this switches: USB = USB_SUPPORT or NO_ USB_SUPPORT PCI = PCI_SUPPORT or NO_ PCI_SUPPORT DNG = DONGLE_SUPPORT or NO_ DONGLE_SUPPORT ISA = ISA_SUPPORT or NO_ ISA_SUPPORT As default all interfaces are enabled. For example if you want to suppress PCAN- Dongle and PCAN-ISA Interfaces you have to compile: cd ~/peak-linux-driver/driver make clean make DNG=NO_ DONGLE_SUPPORT ISA=NO_ ISA_SUPPORT

PCAN-driver for Linux page 13 of 20 3. The following section only applies to kernel versions 2.4.x or smaller: The driver is to be installed on RedHat Linux. RedHat in contrast to SuSE as default uses the „CONFIG_MODVERSIONS“ modifier to prohibit the installation of improper drivers. If your operating system was generated with enabled „CONFIG_MODVERSIONS“ you can see this easily by invoking „cat /proc/ksyms“. If there are cryptic number-letter combinations at the end of the symbols your system was generated with enabled „CONFIG_MODVERSIONS“. A simple new compilation on your system is enough: cd ~/peak-linux-driver/driver make clean make

4. Your operating system doesn't support the PARPORT_SUBSYSTEM or you have a parallel interface which is unknown to the operating system and you like to use a PCAN-Dongle with this interface. Here you have to compile with the „PAR=NO_PARPORT_SUBSYSTEM“ switch: cd ~/peak-linux-driver/driver make clean make PAR=NO_PARPORT_SUBSYSTEM

5. You get runtime errors and want to see more information for diagnosis at „/var/log/messages“. Here you have to translate with the „DBG=DEBUG“ switch:

cd ~/peak-linux-driver/driver make clean make DBG=DEBUG

6. This option is not supported from kernels greater than version 2.6.x: Compiling for devfs-file system support. If you translate the sources for a system with devfs-support (CONFIG_DEVFS_FS = y) this will be considered automatically:

cd ~/peak-linux-driver/driver make clean make DEVFS=DEFS_SUPPORT

Combinations of these switches are also possible.

Prerequisites for compilation of the sources Before compiling following prerequisites have to be considered: 1. Up from kernel version 2.6.x the completely configured kernel sources for your target system have to be installed. If it is a standard installation the sources are located under „/usr/src/linux“ in which this normally is a link e.g. to „/usr/src/linux- 2.6.6“. For every kernel smaller or equal than 2.4.x only the „kernel-headers“ have to be installed. (It's not wrong to install the complete sources of the target system.) The kernel-headers are installed if the invocation of “cat /lib/modules/'uname -r'/build/include/linux/modversions.h“ is ending without an error. (“'uname -r'“ is a

PCAN-driver for Linux page 14 of 20 place holder for the result of the invocation “uname -r“.) 2. The “/lib/modules/'uname -r'/build/include/linux/version.h“ file has to exist or being copied before from the path “/boot/vmlinuz.version.h“. 3. Tools like make, gcc, etc. have to be installed. (To edit or investigate foreign source codes I like to use the source navigator of RedHat. http://www.sourceforge.net/projects/sourcenav )

Support for Cross-Compilation The driver, its library and the test programs sometimes are used on other systems than the development system. The process of generating the binary driver for another target is called Cross-Compilation. Partially the driver and its helper programs are supporting Cross-Compilation. Therefore the driver has to be translated with the option. make KERNEL_LOCATION=

Whether the driver can be translated for every possible target system and is working there can't be guaranteed because of so many different architectures. The installation of the driver and the library on an other target than the host system can't be supported through the given installation scripts. We are glad about hints how to improve the Cross-Compilation support.

FAQs Q. The driver for my PCAN-ISA card is not being installed. What's wrong? A. One possibility is that the SJA-1000 chip on the card is setting back while checking the PeliCAN-mode. If the card with a PLD that has got a red point and the jumper JP11 is set „on“ this may be the reason. Remedy: To set the jumper to „off“.

Q. My PCAN-ISA, OCAN-PC/104 or PCAN-Dongle doesn't receive any data though I can send. What's wrong? A. A possible reason is that a wrong interrupt is configured for the device. Then single telegrams can be send however none can be received. Not only the wrong assertion of the interrupt number but often the missing release of the interrupt in BIOS („legacy ISA“) for the PCAN-ISA card can be the reason. (See also (1*))

Q. My PCAN-Dongle is being rejected while using it even if the installation was successful. What's wrong? A. Normally the reason is a not assigned interrupt for the „parport_pc“ while using it together with the PARPORT_SUBSYSTEM (1*).

Q. What possibilities do I have to diagnose if I have problems? A. Linux has a variety of choices. First it's useful to look at recent messages with: “tail -f /var/log/messages“

PCAN-driver for Linux page 15 of 20 If the driver is loaded you can see (as root) with „/sbin/lsmod | grep pcan“ More informations about the parameter of the driver can be asked with. „/sbin/modinfo pcan“ Closer information about assignment of major- and minor-numbers and about the use of resources can be queried with “cat /proc/pcan“ Information about assignment of resources can be queried with “cat /proc/interrupts“ “cat /proc/ioports“ “cat /proc/iomem“ „cat /proc/pci“ or „cat /proc/bus/pci/devices“ depending on the kernel version. „cat /proc/bus/usb/devices“ Please note that the interrupts of the hardware aren't registered until its use. To diagnose USB there are also programs with a graphical user interface like e.g. „USBView“. With garbled installations sometimes paths for translation of the driver are set wrong. That's why while translating the driver a message like this appears: *** Host machine kernel version=2.4.18-4GB, Driver kernel version=2.6.5, \ Path to kernel sources=/mnt/usr/src/linux, use KBUILD=yes With this message it is possible to compare if the driver is really translated for the used kernel. The „KBUILD“ mechanism is used from kernel 2.6.x on.

Q. How do I interpret the output of “cat /proc/pcan“ ? A. The second line gives information about the release of the driver. In the third line the number of the found CAN-channels and the assigned major-number are shown. From line four on the characteristics of the each CAN-channel are described. The first column shows the minor-number assignment of the channel, the second column shows the type of the channel, the third and fourth column the assignment to base addresses (ports) and interrupt-numbers. The following four columns count the number of processed read-, write-, interrupt- and errors transactions. The last column shows the last occurred error status of the channel. The status is a bit-field with an interpretation like this table:

PCAN-driver for Linux page 16 of 20 Bit Description 0 Chip-send-buffer full 1 Chip-receive-buffer overrun 2 BUS warning 3 BUS passive 4 BUS Off 5 Receive-buffer is empty 6 Receive-buffer overrun 7 Send-buffer is full 14 Illegal parameter

Both columns „base“ and „ir“ are misused with USB channel types. „base“ is showing the serial number of the module and „ir“ the programmed device number of the module. The column „irqs“ in case of type 'usb' counts the number of received or sent USB- packages..

Q. What happens if I plug out the interface while using PCAN-USB? A. First of all your programs will stall and a re-plug-in of the PCAN-USB doesn't change anything. First you have to stop the PCAN-USB using programs and after plugging-in of the interface you can invoke your programs again. It's not guaranteed that the same minor number as the previous PCAN-USB minor-number is allocated. Minor-number assignment depends on the order of plug-ins of PCAN-USB devices.

Q. How can I find out what minor-number the PCAN-USB is assigned to? A. With help of the individual pre-programmed „device-number“, which can be experienced with help of the „/proc/pcan“ interface, a relationship to a special physical connection can be made.

Q. I want to open my PCAN-USB device however I get an error message. What's wrong? A. There is more than one possibility: 1.) The appropriate device is not registered as „/dev/pcan...“. 2.) The appropriate device is not plugged in.

Q. The translation on my system doesn't work. What can be wrong? A. The most common reason are not installed Linux kernel sources. Often sources of another kernel than the one installed are used. Sometimes both files

„/boot/vmlinuz.autoconf.h“ and „/boot/vmlinuz.version.h“ of the distribution are not linked to the files they are assigned to.

„/lib/modules/'uname-r'/build/include/linux/autoconf.h“ and „/lib/modules/'uname -r'/build/include/linux/version.h“

Q. The transmission performance of CAN-messages is low, if I send a telegram with help of the write-interface out of a script. What is the problem? A. Every line in a script opens the path to a device and immediately closes this path

PCAN-driver for Linux page 17 of 20 again. This opening and closing takes time. The transmission performance can be improved by letting open another path. For example:

cat /dev/pcan32 >/dev/null & echo „m s 0x123 2 0x11 0x12“ > /dev/pcan32 echo „m s 0x123 2 0x11 0x12“ > /dev/pcan32

Q. During installation of the driver with USB-support I get following message: „Warning: loading pcan.o will taint the kernel: non-GPL license – Proprietary“. What's the meaning of this message? A. This message points out that the driver for the PCAN-USB module is not released under the GPL license. The use of the driver as a module within Linux though is legal.

Q. The source code module „pcan_usb_kernel.c“ only contains cryptic letters. Is the file destroyed? A. No, the contents of the files are obfuscated to save intellectual property. Though it's still a translatable source code.

Q. I translated for device file system support. Though it's not working. A. Is your devfsd – the „device file system daemon“ – active? Please check that. (With kernel 2.6.x the use of the device file system is depreciated through the kernel developers because of unconquerable system problems. Due to this the PCAN driver does not support the device file system for kernel 2.6.x.)

Q. While translating kernel 2.6.x following warning appears: *** Warning: Overriding SUBDIRS on the command line can cause *** inconsistencies Is something not right? A. I am afraid that the discussion within the kernel-developer community about the right way of translating external modules hasn't found an end until this release. The current way generates this warning and at worst translates all of the modules again. Though there are approaches that the generation of external modules like pcan.ko is getting easier. This message can be ignored.

Q. While translating the driver following message appears: *** "Can't find /usr/src/linux-2.4.24.SuSE/include/linux/version.h !". End. What's the problem? A. Within the driver makefile up from version 3.3 the target kernel version is not being won out of the interpretation of the command 'uname -r', but extracted out of contents of the file „$(KERNEL_LOCATION)/include/linux/include/version.h“. (If there wasn't any special „KERNEL_LOCATION“ given at the command line of „make“ „KERNEL_LOCATION=/usr/src/linux“ is being used as default.) While translating the kernel sources the file „version.h“ is generated. Normally this message has its cause in not translated kernel sources. Until kernels 2.4.x it was enough if the distribution had installed this file. From kernel 2.6.x on it is necessary that the kernel sources for the target system are configured and translated completely. Then the file „version.h“ is being created.

Q. I got other questions or problems with the driver. A. Please consult [email protected].

PCAN-driver for Linux page 18 of 20 Q. I am enthusiastic about the driver or the documentation and want to contribute something to make it better. Who do I have to consult? A. Please also contribute [email protected]. Peak and the author are happy about every positive response.

Appendix (1*) = The „Parport Subsystem“ has to be configured to use a interrupt. Therefore following lines have to be entered into the file „/etc/modules.conf“ or „/etc/modprobe.conf“ depending on your kernel version: alias parport_lowlevel parport_pc options parport_pc io=0x378 irq=7

Normally „irq=none“ stands in the „options“-line. The assigned interrupt number must match the assigned interrupt number of the device. Those works can only be done as 'root“. If the „Parport Subsystem“ is already installed it can be removed with: rmmod lp and/or rmmod pcan rmmod parport_pc rmmod parport

(2*) = You are not forced to use the „Parport Subsystem“. Then the alternately use of the parallel port through PCAN-Dongle and e.g. a printer is not possible any more. For it the driver has to be translated with the PAR=NO_PARPORT_SUBSYSTEM option. Then the previous detail of „modprobe parport“ is not necessary while installing.

(3*) = For each type of hardware 8 device-interfaces are reserved. For PCI those are the minor-numbers 0...7, for ISA 8...15, for Dongle in SP-mode 16...23 and for Dongle in EPP-mode 24...31, for PCAN-USB 32..39. Therefore the device files have a name e.g.: /dev/pcan0 for the first PCI-channel /dev/pcan8 for the first ISA-channel /dev/pcan16 for the first SP-channel /dev/pcan24 for the first EPP-channel /dev/pcan32 for the first USB-channel (9*)

The invocation of „pcan_make_devices n“ however only creates n device files of each type. According to your demands „n“ can be any number from 1...8.

(4*) = In some cases the dynamic assignment of „major“- device numbers are unwelcome. However this can be changed in the driver sources (file „pcan_main.h“, constant „PCAN_MAJOR“). Afterwards the driver has to be translated and installed again. The best is to use the number „91“. This already is intended for CAN-devices. Please note that conflicts to other installed CAN-drivers can be possible.

(5*) = The „read“- and „write“-interface of the driver print out ASCII formatted data or accept ASCII formatted data as input. The format of the telegrams for „read“ and „write“

PCAN-driver for Linux page 19 of 20 is defined identically, so that a redirection of data is possible: cat /dev/pcan0 > /dev/pcan8

The format of the data is like the previously mentioned description of the telegrams. Additionally to the description of the telegrams the „read“-output supplies a time stamp in milliseconds. If there is a redirection like above the time stamp is being ignored. The „write“-output also accepts details about initializing: cat „i 0x1234 e“ > /dev/pcan8

The first parameter pinpoints the initialization, the second parameter names an input value for both BTR0/BTR1 registers of the SJA1000 chip. The optional third parameter „e“, enables the accept ion of extended frames. Naturally a faster „ioctl()“-interface is also defined.

(6*) = CAN hardware is only accepted based on Philips chip SJA1000. PCAN-ISA or -PCI hardware is immediately verified during installation. In contrast to that the PCAN -Dongle hardware is not verified until an „open()“ call. That's the reason why no error is reported if a parallel port without plugged-in PCAN-Dongle is recognized .

(7*) = Sometimes some hardware/software combinations don't recognize the USB- Dongle after a new start of the system. The red light-emitting diode doesn't shine at the PCAN-USB if that's the case.

(8*) = If lots of faults are generated with enabled USB support while translating, then a faulty Linux kernel configuration may be the cause. During configuration of the Linux kernel the USB-support has to be enabled.

(9*) = From kernel version 2.6 on the behaviour during assignment of the „minor“-numbers is being changed through the kernel parameter „CONFIG_USB_DYNAMIC_MINORS“. When „CONFIG_USB_DYNAMIC_MINORS“ is set, the first free „minor“-number is assigned to from 0 on. Mandrake distributions uses this configuration.

This document was made with help of OpenOffice.org (http://www.openoffice.org). Thanks to the community for such an excellent tool.

Linux, SuSE, RedHat, Mandrake, Windows are trademarks of the appropriate owners.

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